<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
    *{
        margin: 0;
        padding: 0;
        outline: 0;
    }
    .clearfix:after{
        content:'';
        display: block;
        clear: both;
    }
    .green {
        background-color: green;
    }
    .orange {
        background-color: orange;
    }
    .w150 {
        width: 150px;
        height: 150px;
    }
    main {
        height:100px;
    }
    /* main,aside {
        float: left;
    } */
    .left {
        float: left;
    }
    .right{
        float: right;
    }
    .grail {
        /* 圣杯式布局 三列式布局  padding把左右侧边栏的位置让出来 */
        padding: 0 150px;
    }
    .grail main {
        float: left;
        width: 100%;
    }
    .grail .left{
         margin-left: -100%;
         position: relative;
         left: -150px;
    }
    .grail .right {
        float: left;
        margin-left: -150px;
        right: 150px;
        position: relative;
    }
    </style>
</head>
<body>
    <div class="layput">
        <h4>方法一：圣杯布局</h4>
        <section class="grail clerafix">
            <!-- 实现自适应 -->
            <main class="green">main</main>
            <aside class="w150 left orange">aside</aside>
            <aside class="w150 right orange">aside</aside>
        </section>
    </div>
</body>
</html>